Cartridge crystal holder



Feb. 19, 1946. s. A. BoKovoY CARTRIDGE CRYSTAL HOLDER Filed June 8, 1943 n a o IN VEN TOR. 5mm/2 A. ,9o/ro v0 Y BY l , Ml( mi* Patented Feb. 19, i946 CARTRIDGE CRYSTAL HOLDER n Samuel A. Bokovoy, Verona, N. J., asslgnor to Federal Telephone and Radio Corporation, New York, N. Y., a corporation of Delaware Application June 8, 1943, Serial No. 490,027

7 Claims.

This invention relates to piezo-electric oscillator or resonator units for crystal controlled oscillator circuits and the like and consists of an improved unit assembly of crystal and holder 'therefor which is particularly simple Iand economical in manufacture and offers important advantages particularly in the manner of support for the crystal as a result of which the vibration of the crystal element is restrained to the minimum or to a negligible degree.

To this end, the improved unit consists of a substantially rectangular crystal element supported within a holder of preferably hollow cylindrical form with the crystal disposed in an oblique position therein so as to have point contact only with the internal cylindrical surface of the holder at each end thereof and at pposite sides of the respective crystal end portions thereby to reduce to the minimum any damping effect on the crystal vibration. This crystal mounting arrangement further permits of a structural embodiment of desired simplicity wherein the cylindrical holder is made of glass tubing to which are fitted end terminal caps having internally connected therewith spring contact elements engaging with the crystal from opposite sides, resiliently to secure it in position and t0 establish electrical connection thereto at its end portions. There is thereby provided with utmost simplicity, a resonator unit wherein the crystal is securely positioned and in a manner to permit unrestrained vibration thereof. It moreover lends itself readily to exhausting of the container for improved operation and greater prOleC- tion and durability. In addition the improved holder further readily accommodates crystals of altered thickness and dimensions permitting a desirable range of adjustment of oscillation values to meet varied circuit conditions or requirements.

The foregoing and other features and advantages of the present invention will be more fully understood by reference to the accompanying drawing wherein like reference characters are applied to the corresponding parts in the several views.

In the drawing:

Fig. 1 is a vertical, longitudinal, sectional view of the improved oscillator unit of the present invention.

Fig. 2 isa vertical, cross-sectional view thereof taken on line 2-2 of Fig. 1.

Fig. 3 is a perspective view of the crystal element partially broken away indicating the manner of support.

In the preferred embodiment of the features of the present improvements, as illustrated, the

crystal resonator unit is of a cartridge type wherein the holder or container for the crystal element is composed of a section of hollow cylindrical glass tubing I, or tubing of other suitable insulating material such as Isolantite or Bakelite, the ends of which are closed by metal terminal cap members 2 providing end walls and annular flanges 3 overlying the tube ends and permanently secured thereto by a suitable sealing cement.

Within the cylindrical tube there is supported, in the oblique position as shown, the crystal oscillator or resonator element 4 of elongated rectangular form and of suitable length for spaced relation with reference to the end walls of the container. The resonator element is shown as the customarily employed crystal having its opposite larger ilat surfaces provided with the usual metallic electrode coating such as silver. As a result of its oblique position, in conjunction with the cylindrical or curved inner surface of the tube engaged thereby, the crystal as will be noted is supported by corner edge or point contact only at its end portions, the point supporting contacts being as shown in Fig. 3 at :rat the upper corner edges at one end of the crystal and at the lower corner edges y-y at the opposite end thereof. The two point support of the crystal at each end and at opposite sides thereof, las thus provided, permits of uninterrupted vibration of the crystal body throughout the full length thereof while at the same time ailording substantial support therefor.

The crystal is retained in its supporting position under resilient pressure by the engagement therewith of the flat metal spring contact members 8 6 secured by bracing to the inner walls of the cap terminals and formed with the reverse turn spring contact portions 1-1 having pressure engagement with the upper and lower surfaces, respectively, of the crystal as shown. The spring contact members, in the reversely directed arrangement as shown, provide for effective electrical contact with the silvered coating of the resonator and incident to their position of engagement, at opposite sides of and adjacent the crystal extremities, have a negligible restraining effect or damping of the crystal vibration.

As will be appreciated, the improved resonator unit is particularly simple and economical to make, may readily be evacuated for operation under most favorable conditions,y is adapted to accommodate crystals varied in size or thickness -ilrmly retained in its proper position safe from dislodgement under normal usage.

While I have shown and described an approved embodiment of the features of the present invention, it will be understood that varied modincations may be made therein without departing from the scope of the invention as denned in the appended claims. It is accordingly intended that all matter herein shall be interpreted as illustrative and not'in a limiting sense.

Having described my invention I claim:

1. A frequency determining unit of the character described comprising a tubular container member and a crystal element of substantially rectangular form positioned obliquely within the container, each end of the crystal element making contact at two points thereof respectively and at opposite sides thereof with the inner surface of the container.

2. A frequency determining unit of the character described comprising a container providing an enclosure and support for a piezo-electric crystal element and a crystal element of rectangular form positioned therein to have corner supporting contact only at its respective ends and at the opposite sides thereof.

3. A piezo-electric structure comprising a tubular container member, a crystal element of substantially rectangular form positioned obliquely within the container, each end of the crystal element engaging at two corner points thereof respectively and at opposite sides thereof with the inner surface of the container, and resilient contact members arranged to provide resilient support for the end portions of the sides opposite the points of engagement.

4. A frequency determining unit of the character described comprising a hollow cylindrical insulating container member, a crystal element of substantially rectangular form positioned oblquely within the container member for corner asoaoss of the and resilient terminal cmtact memberspositionedtoengsgeendportionsofthe .sidesoppositethepointsofmementard electricallyconnected to the cap members.

5.Afrequency determiningunitofthecharacter described comprising an elongated tubular insulating container member, a crystal element of substantially rectangular form positioned obliquely and lengthwise within the container to have corner supporting engagement with the inner surface of the container at the ends and at opposite edges of the crystal element, terminal capmembersilttedtoclosetheendsoi'thecontainer member and resilient contact members of electrical conducting material-connected to the inner surfaces of the cap members and Yformedwithinwardlyextendingandrevex'sely turned resilient contact portions positioned to engage the end portions of the Crystal faces opposite the points of mement for retaining the position of the crystal element and making electrical connection thereto.

6. A piezo-electric crystal assembly comprising a support of insulating material formed to provide inner surfaces oppositely directed, a crystal element positioned in angular relation to said surfaces to have corner supporting contact therewith for end supporting engagement only at the opposite sides of the respective ends of the crystal and resilient pressure elements supported for pressure engagement with the crystal end portions at the sides opposite to the supporting contact.

7. A piezo-electric crystal bly comprising a support of insulating material formed to provide inner surfaces oppositely directed, a crystal element of substantially rectangular plate form positioned in angular relation to said surfaces to have corner supporting contact therewith for end supporting engagement only at the opposite sides of the respective ends of the crystal, said crystal being provided on its faces with electrode plating and resilient contact elements supported for pressure engagement with the electrodes at tl e supporting engagement at opposite sides of the I crystal element with the internal surface of the container, terminal cap members closing the ends sides opposite to the supporting contact of the crystal.

SAMUEL A. BOKOVOY. 

